Chilli-coated rope fences, fast catching on as a cost-effective tool against crop raiding elephants, curiously deter female elephants far more than they do the male of the species, finds an experiment by researchers from the Indian Institute of Science and Asian Nature Conservation Foundation.

Studies conducted in three forest villages found a clear “gender bias” in the efficacy of the chilli rope: while almost all females were taken in by the “rope trick”, more than half the male elephants cast aside the noxious rope and got on with business as usual. The chilli-rope is, however, a simple, cost-effective and safe tool for barricading fields, says the research paper published in the latest edition of Current Science.

In the experiment, three forest villages were encircled with a jute or cotton rope coated with a mixture of chilli, tobacco and engine grease. The three forest villages, chosen for their history of chronic human-elephant conflicts, are located in Buxa Tiger Reserve (West Bengal); in Wayanad Wildlife Sanctuary in Kerala; and in Hosur Forest Division, Tamil Nadu.

As many as 20 out of 21 approaching female herds turned away when they encountered the rope, while 22 out of 38 male elephants walked right through the barriers. Almost all elephants were found to explore the fence, sniffing it with their trunks, and walking along it for several metres. Interestingly, African elephants have been known to respond more dramatically to chilli-tobacco fences: raising an alarm, shaking their head and making hasty retreats.

Researchers also found that the rope fence was easily rendered ineffective by rain and even dew. For instance in Gulatti village in Buxa Tiger Reserve, the driest of the three sites, showed the smallest proportion of rope breaches.

However, the chilli-tobacco fence is an effective method to prevent raids by female-led herds and especially in low-rainfall areas, concludes the paper authored by K. Chelliah, G. Kannan, S. Kundu, N. Abilash, A. Madhusudan, N. Baskaran and R. Sukumar.

At Rs. 500/km, installing and maintaining a chilli-tobacco fence costs less than deep trenches or high-voltage electric fences, the authors pointed out. Applied once in three days for three months leading up to harvest, the cost of the rope works out to Rs. 12,000/km.

In comparison, elephant-proof trenches cost approximately Rs. 1,00,000/km and non-lethal electric fences Rs. 1,50,000/km.

They add that there were still some areas that require greater study.

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